So my plan after reading this article on one of my favorite car sites was to spend a day or two at the local Pull-a-Part gathering 2 1/2 in. OD exhaust pieces. I would then cut into sections as required and reassemble to fit under the civic. With careful selection I could keep the hacking and welding and general wasting of time to a minimum. However, somewhat to my surprise the only vehicles on the yard with anything near 2 1/2 in. OD exhaust tubing were the full-sized GM trucks and vans with 2.6 in. tubing. And the trouble with those systems, as I came to realize is that the only straight part of the system with any length is made out of 3ft worth of muffler. The remaining portion of the system is made up of a series of small, snake-y kinks and bends that wind up and over the rear solid axle. not great for repurposing under a civic that requires all of two 45º bends, a 90º bend, an offset kink around the shifter and an "S" through the rear suspension.
After scrapping that plan, I move right along to plan bee which was a mandrel bent kit from Truebendz Technology. You can find their aftermarket web store at mandrelexhaustsystems.com. I emphasized the word "kit" because like a kit car you can pull it out of the box, assemble and go. but if you want something good, that fits together well and is easy to work on and work with you'll want to do some cutting and modifying.
That's exactly what I've done. So for $145 shipped I received enough pre-bent tubing to save myself time in fabricating a custom built, custom fitting mandrel bent exhaust system. Here is what comes in the kit... (ignore the muffler and resonator in the background.)
A box of clamps, bolts, hangers and a flange with gasket. It would get the job done, but I have a few changes in mind.
First of all I need to add this resonator- which is just a louvered "glasspack" found on Summit Racing's website and made by Jones Exhaust. Aluminized steel to match the tubing. It's available with stubs, a feature I wouldn't need so I ordered the plain one. After some measuring I add it to the section of pipe in the same location as the original to take advantage of the space and heat shielding already in place.
Below shows the internals of the resonator and its louvers from one direction and then the other. It can be installed either direction. With the openings toward the engine gives increased attenuation... it works better to hush things. Other way around is supposed to give better flow. I went with the quieter since this is a daily driven street car and I leave for work pretty early in the morning. I like getting along well with the neighbors.
I want to be able to unbolt and disassemble things in the future- easily. To allow for that I add a flanged joint instead of the U-bolt clamps in the kit. U-bolt clamps aren't really doing their job until they've crimped the tubing. As you can imagine this makes mandrel bends sad and gets me grouchy when time comes for separation.
What else...? A temporary adapter at the factory down pipe flange coming from the catalytic converter/manifold. I fit this to the pipe with a lap-joint band clamp also from Summit. I'll use another just like it to hold on the muffler once again to facilitate easy removal and substitutions. (see in muffler connector pipe image below)
Oh, and the muffler I'm using is also a Jones Exhaust brand. In particular, an 18in. long, stainless, center inlet, offset outlet (works in either direction), 5 x 8 oval "Full Boar MaxFlow." In construction and quality it's virtually the same as a Magniflow. Two advantages over the more popular Magniflow: the perforated tube through the middle is mandrel bent and the price is kept low by their lack of advertising. At least I assume that's the case since the muffler and resonator together cost $78 shipped (compared to $106 for the Magniflow muffler alone) and the fact that I've had not heard of them before stumbling upon their products on Summit.
That takes care of the planned changes. After the first test fit I quickly realized that some changes to the mandrel bends would be required. The S-bend through the rear suspension sat too far forward and also placed the inlet to the muffler much lower than I would like. The fix I came up with is to remove about 4in. from the straight section between the hump and final turn into the muffler and relocate it to the front of the section where I would be adding the flanged connection. I used the bandsaw at work to make for an extra straight and tidy cut. This helped avoid any misalignment or general wonkiness. It also makes welding much easier when there are no gaps to fill.
I took my time with the hangers to get them just right. I curved the front around to match the shape of the tubing. The side hanger here was simplified into a "Z" shape.
The rear hangers on the muffler were actually borrowed from a spare factory muffler I had. I added a section of round bar stock to replace the stamped piece which actually hung too low for the intended muffler position. I put them in place under the car and tacked two "C" shaped links, one on either side to hold set the fit. finished welding and cut off the excess. I'm really happy with the outcome!
I finished off all of the welds with some heat resistant "aluminum casting" colored spray paint to deter rust since I used mild steel, flux-core welding wire. All of the tubing and the resonator are aluminized and the muffler and hangers are stainless so rusty welds would stick out like a sore thumb were anyone to have a peek under the car. Shabby. Flanges were also mild steel so they got a few coats as well.
From inside the car the sound at startup is nearly the same as stock. I was amazed! At low rpm when accelerating (or on deccel) there is a mild, deep tone. Not stock sounding but nothing I would consider loud even at full throttle. It's a suitable sound from a car that's essentially a compact family hauler/grocery getter. I didn't expect much change in performance due to the 2.5in. OD being a bit big for the existing 1.6, unmodified engine. Driveability doesn't seem to have suffered any. I have noticed less effort accelerating uphill at interstate speeds so I suppose it's freed up a few HP in the mid to upper range. I do however expect the sound to change though when the "built" 2.3L is breathing through it sans cat. and with a custom header.
Enjoy the surplus images:
Check back soon- I may do a video...
After scrapping that plan, I move right along to plan bee which was a mandrel bent kit from Truebendz Technology. You can find their aftermarket web store at mandrelexhaustsystems.com. I emphasized the word "kit" because like a kit car you can pull it out of the box, assemble and go. but if you want something good, that fits together well and is easy to work on and work with you'll want to do some cutting and modifying.
That's exactly what I've done. So for $145 shipped I received enough pre-bent tubing to save myself time in fabricating a custom built, custom fitting mandrel bent exhaust system. Here is what comes in the kit... (ignore the muffler and resonator in the background.)
A box of clamps, bolts, hangers and a flange with gasket. It would get the job done, but I have a few changes in mind.
Below shows the internals of the resonator and its louvers from one direction and then the other. It can be installed either direction. With the openings toward the engine gives increased attenuation... it works better to hush things. Other way around is supposed to give better flow. I went with the quieter since this is a daily driven street car and I leave for work pretty early in the morning. I like getting along well with the neighbors.
I want to be able to unbolt and disassemble things in the future- easily. To allow for that I add a flanged joint instead of the U-bolt clamps in the kit. U-bolt clamps aren't really doing their job until they've crimped the tubing. As you can imagine this makes mandrel bends sad and gets me grouchy when time comes for separation.
What else...? A temporary adapter at the factory down pipe flange coming from the catalytic converter/manifold. I fit this to the pipe with a lap-joint band clamp also from Summit. I'll use another just like it to hold on the muffler once again to facilitate easy removal and substitutions. (see in muffler connector pipe image below)
Oh, and the muffler I'm using is also a Jones Exhaust brand. In particular, an 18in. long, stainless, center inlet, offset outlet (works in either direction), 5 x 8 oval "Full Boar MaxFlow." In construction and quality it's virtually the same as a Magniflow. Two advantages over the more popular Magniflow: the perforated tube through the middle is mandrel bent and the price is kept low by their lack of advertising. At least I assume that's the case since the muffler and resonator together cost $78 shipped (compared to $106 for the Magniflow muffler alone) and the fact that I've had not heard of them before stumbling upon their products on Summit.
That takes care of the planned changes. After the first test fit I quickly realized that some changes to the mandrel bends would be required. The S-bend through the rear suspension sat too far forward and also placed the inlet to the muffler much lower than I would like. The fix I came up with is to remove about 4in. from the straight section between the hump and final turn into the muffler and relocate it to the front of the section where I would be adding the flanged connection. I used the bandsaw at work to make for an extra straight and tidy cut. This helped avoid any misalignment or general wonkiness. It also makes welding much easier when there are no gaps to fill.
I took my time with the hangers to get them just right. I curved the front around to match the shape of the tubing. The side hanger here was simplified into a "Z" shape.
The rear hangers on the muffler were actually borrowed from a spare factory muffler I had. I added a section of round bar stock to replace the stamped piece which actually hung too low for the intended muffler position. I put them in place under the car and tacked two "C" shaped links, one on either side to hold set the fit. finished welding and cut off the excess. I'm really happy with the outcome!
I finished off all of the welds with some heat resistant "aluminum casting" colored spray paint to deter rust since I used mild steel, flux-core welding wire. All of the tubing and the resonator are aluminized and the muffler and hangers are stainless so rusty welds would stick out like a sore thumb were anyone to have a peek under the car. Shabby. Flanges were also mild steel so they got a few coats as well.
From inside the car the sound at startup is nearly the same as stock. I was amazed! At low rpm when accelerating (or on deccel) there is a mild, deep tone. Not stock sounding but nothing I would consider loud even at full throttle. It's a suitable sound from a car that's essentially a compact family hauler/grocery getter. I didn't expect much change in performance due to the 2.5in. OD being a bit big for the existing 1.6, unmodified engine. Driveability doesn't seem to have suffered any. I have noticed less effort accelerating uphill at interstate speeds so I suppose it's freed up a few HP in the mid to upper range. I do however expect the sound to change though when the "built" 2.3L is breathing through it sans cat. and with a custom header.
Enjoy the surplus images:
final fitment.
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